Aggressive regimens of insulin management result in more frequent episodes of hypoglycemia. Some patients do not develops symptoms of hypoglycemia but have signs of neuroglycopenia as the initial manifestation of hypoglycemia. It is important to investigate and validate a sensitive method to detect early deterioration in cerebral function. The reaction time task and P300 latency represent potential modalities for early detection of neuroglycopenia and identification of patients at high risk for hypoglycemia.